A novel multiscale approach to brittle fracture of nano/micro‐sized components

Principles and advantages of a new concept based on the ab initio aided strain gradient elasticity theory are shown in comparison with the classical Barenblatt cohesive model. The method is applied to the theoretical prediction of the critical energy release rate and the crack tip opening displaceme...

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Bibliographic Details
Published in:Fatigue & fracture of engineering materials & structures 2020-08, Vol.43 (8), p.1630-1645
Main Authors: Kotoul, Michal, Skalka, Petr, Profant, Tomáš, Řehák, Petr, Šesták, Petr, Černý, Miroslav, Pokluda, Jaroslav
Format: Article
Language:English
Subjects:
Computation
Continuum mechanics
Crack opening displacement
Crack tips
Cubic lattice
DFT
Displacements (lattice)
Elasticity
Energy release rate
FEM
fracture nanomechanics
Germanium
Molybdenum
Multiscale analysis
Screw dislocations
size‐dependent phenomena
Strain
strain gradient elasticity
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Summary:Principles and advantages of a new concept based on the ab initio aided strain gradient elasticity theory are shown in comparison with the classical Barenblatt cohesive model. The method is applied to the theoretical prediction of the critical energy release rate and the crack tip opening displacement at the crack instability in nanopanels made of germanium and molybdenum crystals. The necessary length scale parameter l1 is determined for germanium and molybdenum by the best gradient elasticity fits of ab initio computed screw dislocation displacements and phonon dispersions. Values of ab initio computed critical energy release rates and crack opening profiles revealed that the length l1 is related to inflexion points of profiles. A novel ab initio method in combination with continuum mechanics was successfully tested to replace molecular statics dependent of availability of interatomic potentials. The asymptotic strain gradient elasticity solution for displacement components near the crack tip in materials with cubic lattice was also derived.
ISSN:8756-758X
1460-2695
DOI:10.1111/ffe.13179